function s1_goto_dir(){
         cd "$1"
}
function s2_touch_empty_file_with_given_name(){
         touch "$1"
}
function s3_make_directories(){
        mkdir -p ./projects/{git,backup}
}
function s4_create_6_files(){
        touch ./projects/linux{1,2}_{centos,redhat,c_programming}
}
function s5_make_directories_in_git(){
         mkdir -p ./projects/git/linux{1,2}
}
function s6_move_files_to_dir_1_or_2(){
         mv ./projects/linux1* ./projects/git/linux1
         mv ./projects/linux2* ./projects/git/linux2
}
function s7_create_package_and_compress(){
         tar -czvf ./projects/backup/git.tar.gz ./projects/git
}
function s8_delete_dir_git(){
         rm -rf./projects/git
}
function s9_recover_from_git_tar_gz_backup(){
         tar -zxvf ./projects/backup/git.tar.gz  ./projects/
}
function s10_create_package_and_compress(){
         tar -jcvf ./projects/backup/git.tar.bz2 ./projects/git
}
function s11_find_and_sort_alphabetically_all_created_files_and_dirs(){
         find ./projects | sort
}
function s12_get_next_15_minutes_boundary(){
        date -d @$(( (($(date +%s)+ 900 - 1)/900)*900))"+%Y-%m-%d_%H:%M:%S"
}

